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Journal of Personalized Medicine Oct 2023This review of the use of vasopressin aims to be comprehensive and highly practical, based on the available scientific evidence and our extensive clinical experience... (Review)
Review
This review of the use of vasopressin aims to be comprehensive and highly practical, based on the available scientific evidence and our extensive clinical experience with the drug. It summarizes controversies about vasopressin use in septic shock and other vasodilatory states. Vasopressin is a natural hormone with powerful vasoconstrictive effects and is responsible for the regulation of plasma osmolality by maintaining fluid homeostasis. Septic shock is defined by the need for vasopressors to correct hypotension and lactic acidosis secondary to infection, with a high mortality rate. The Surviving Sepsis Campaign guidelines recommend vasopressin as a second-line vasopressor, added to norepinephrine. However, these guidelines do not address specific debates surrounding the use of vasopressin in real-world clinical practice.
PubMed: 38003863
DOI: 10.3390/jpm13111548 -
Cureus Aug 2023Sarcoidosis is an inflammatory condition that can impact multiple organs in the body such as the lungs, skin, eyes, and, occasionally, the central nervous system. When...
Sarcoidosis is an inflammatory condition that can impact multiple organs in the body such as the lungs, skin, eyes, and, occasionally, the central nervous system. When sarcoidosis affects the nervous system, it is referred to as neurosarcoidosis and is estimated to occur in approximately 5%-15% of sarcoid patients. When neurosarcoidosis affects the pituitary gland, it can result in panhypopituitarism, which can be life-threatening. A 35-year-old male with a known diagnosis of sarcoidosis by skin biopsies presented to the hospital with altered mental status, hypernatremia, hypotension, and hypothermia. He reported symptoms of polyuria and polydipsia for several weeks before admission. Laboratory workup revealed elevated serum sodium at 167 mmol/L, high serum osmolality at 381 mOsm/kg, and low urine osmolality at 381 mOsm/kg, consistent with diabetes insipidus. Anterior pituitary hormone profile workup revealed low 8 am serum cortisol (1.9 mcg/dL) and inappropriately normal adrenocorticotropic hormone (ACTH) (34 pg/ml), low serum free testosterone (<2.5 ng/dL), low luteinizing hormone (0.7 mIU/ml), low follicular stimulating hormone (< 2.6 mIU/ml), low free T4 at 0.4 ng/dL. and inappropriately normal thyroid-stimulating hormone (TSH) at 2.77 uIU/mL. Serum prolactin was mildly elevated at 86.8 ng/mL. Angiotensin-converting enzyme level was within the normal range at 33 U/L. A diagnosis of panhypopituitarism was made. Brain MRI revealed a 3 cm mass in the suprasellar region involving the hypothalamus and bilateral optic tracts with a mass effect on the anterior third ventricle. No discrete pituitary or stalk lesion was identified. A ventriculostomy tube was placed for developing hydrocephalus. A biopsy of the suprasellar mass revealed non-caseating granuloma, confirming neurosarcoidosis. Treatment was initiated with high-dose IV corticosteroids to manage secondary adrenal insufficiency and neurosarcoidosis. He was also started on IV desmopressin and IV levothyroxine to manage his diabetes insipidus and central hypothyroidism. He was transitioned to oral therapy upon discharge. Panhypopituitarism secondary to neurosarcoidosis is a rare presentation that can occur due to the infiltration of the pituitary gland or the infiltration of the hypothalamus affecting the hypothalamic-pituitary axis. Neurosarcoidosis should be considered a differential when evaluating patients with symptoms consistent with panhypopituitarism. Prompt diagnosis and initiation of corticosteroids and deficient hormones can be lifesaving.
PubMed: 37692696
DOI: 10.7759/cureus.43169 -
Clinical Chemistry and Laboratory... Jul 2023Detection of hemoglobin (Hb) and red blood cells in urine (hematuria) is characterized by a large number of pitfalls. Clinicians and laboratory specialists must be... (Review)
Review
Detection of hemoglobin (Hb) and red blood cells in urine (hematuria) is characterized by a large number of pitfalls. Clinicians and laboratory specialists must be aware of these pitfalls since they often lead to medical overconsumption or incorrect diagnosis. Pre-analytical issues (use of vacuum tubes or urine tubes containing preservatives) can affect test results. In routine clinical laboratories, hematuria can be assayed using either chemical (test strips) or particle-counting techniques. In cases of doubtful results, Munchausen syndrome or adulteration of the urine specimen should be excluded. Pigmenturia (caused by the presence of dyes, urinary metabolites such as porphyrins and homogentisic acid, and certain drugs in the urine) can be easily confused with hematuria. The peroxidase activity (test strip) can be positively affected by the presence of non-Hb peroxidases (e.g. myoglobin, semen peroxidases, bacterial, and vegetable peroxidases). Urinary pH, haptoglobin concentration, and urine osmolality may affect specific peroxidase activity. The implementation of expert systems may be helpful in detecting preanalytical and analytical errors in the assessment of hematuria. Correcting for dilution using osmolality, density, or conductivity may be useful for heavily concentrated or diluted urine samples.
Topics: Humans; Hematuria; Peroxidase; Hemoglobins; Erythrocytes; Osmolar Concentration
PubMed: 37079906
DOI: 10.1515/cclm-2023-0260 -
Communications Biology Oct 2023TRPM8 is a non-selective cation channel permeable to both monovalent and divalent cations that is activated by multiple factors, such as temperature, voltage, pressure,...
TRPM8 is a non-selective cation channel permeable to both monovalent and divalent cations that is activated by multiple factors, such as temperature, voltage, pressure, and changes in osmolality. It is a therapeutic target for anticancer drug development, and its modulators can be utilized for several pathological conditions. Here, we present a cryo-electron microscopy structure of a human TRPM8 channel in the closed state that was solved at 2.7 Å resolution. Our structure comprises the most complete model of the N-terminal pre-melastatin homology region. We also visualized several lipids that are bound by the protein and modeled how the human channel interacts with icilin. Analyses of pore helices in available TRPM structures showed that all these structures can be grouped into different closed, desensitized and open state conformations based on the register of the pore helix S6 which positions particular amino acid residues at the channel constriction.
Topics: Humans; Cryoelectron Microscopy; Membrane Proteins; Temperature; TRPM Cation Channels
PubMed: 37857704
DOI: 10.1038/s42003-023-05425-6 -
Nature Nov 2023Optimum protein function and biochemical activity critically depends on water availability because solvent thermodynamics drive protein folding and macromolecular...
Optimum protein function and biochemical activity critically depends on water availability because solvent thermodynamics drive protein folding and macromolecular interactions. Reciprocally, macromolecules restrict the movement of 'structured' water molecules within their hydration layers, reducing the available 'free' bulk solvent and therefore the total thermodynamic potential energy of water, or water potential. Here, within concentrated macromolecular solutions such as the cytosol, we found that modest changes in temperature greatly affect the water potential, and are counteracted by opposing changes in osmotic strength. This duality of temperature and osmotic strength enables simple manipulations of solvent thermodynamics to prevent cell death after extreme cold or heat shock. Physiologically, cells must sustain their activity against fluctuating temperature, pressure and osmotic strength, which impact water availability within seconds. Yet, established mechanisms of water homeostasis act over much slower timescales; we therefore postulated the existence of a rapid compensatory response. We find that this function is performed by water potential-driven changes in macromolecular assembly, particularly biomolecular condensation of intrinsically disordered proteins. The formation and dissolution of biomolecular condensates liberates and captures free water, respectively, quickly counteracting thermal or osmotic perturbations of water potential, which is consequently robustly buffered in the cytoplasm. Our results indicate that biomolecular condensation constitutes an intrinsic biophysical feedback response that rapidly compensates for intracellular osmotic and thermal fluctuations. We suggest that preserving water availability within the concentrated cytosol is an overlooked evolutionary driver of protein (dis)order and function.
Topics: Cell Death; Cytosol; Homeostasis; Macromolecular Substances; Osmolar Concentration; Pressure; Proteins; Solvents; Temperature; Thermodynamics; Time Factors; Water
PubMed: 37853127
DOI: 10.1038/s41586-023-06626-z